Furnace



Oct. 26, 1937. I J. H. NOBLE 2,096,321

- FURNACE Fil so, 19sa- INVENTOR.

Jam? /7. Nob/e QJWW ATTORNEYS Patnted Oct. 26, 1937 UNITED STATES aosasci PATENT oer-res The main objects of my invention are:

First, to provide a hot air furnace of the oil burning type, characterized by the emciency thereof.

- Second, to provide a furnace of the type described, having a relatively large tubular heating area and a ready circulation of air thereby.

Third, to provide a furnace of the type described, which is composed of parts readily disassembled for cleaning purposes.

Fourth, to provide a furnace of the type described, characterized by novel provisions for preheating, the combustion air therefor.

Fifth, to provide a furnace having improved humidity regulation. I

Further objects relating to details and economies of my invention will definitely appear from the description to follow. The invention is defined in the claims.

A preferred embodiment of my invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a vertical sectional view through a furnace embodying my invention, on the line l-l of Fig. 2.

Fig. 2 is a horizontal section on the line 2--2 of Fig. 1, illustrating the arrangement of the tubes and combustion gas manifold of my furnace.

Fig. 3 is an enlarged fragmentary view partially in section, illustrating a detail of the tube construction of my improved furnace.

The present invention is concerned with the production of an improved hot air furnace of the oil burning type, although the essentials of the invention are not restricted to the oil burning type of furnace and may equally well be applied in connection with systems-embodying different. types of combustion, for instance, coal, gas, etc. The furnace is characterized by the unusually large-heating contact area furnished by a plurality of U-shaped upstanding tubes of relatively small diameter per se, said tubes extending substantially of the heightof the furnace casing and being readily removable and taken down for cleaning purposes.

Further, my invention comprises novel provisions whereby the manifold for receiving products of combustion from a combustion chamber .may be thoroughly and. quickly cleaned. Other' aspects of my invention will become apparent 50 from the description to follow.

Referring to the drawing, the reference numeral l indicates a cylindrical sheet metal casing' having a conical dome 2 provided with hot air conduit collars or nipples 3 radiating there- 65.1mm. The casing is closed by a removable sheet metal top 4. 5 represents the floor of a basement or other room housing the furnace.

Supported on suitable legs or uprights 6, I mount a combustion chamber, generally indicated 1, consisting of a dome 8 and floor 9. The chamber is suitably lined with fire clay, fire brick 'or other analogous material I ll. An opening is formed in the bottom of the combustion chamber to receive the burner l l, preferably an oil burner. Alternatively, as stated above, the oil burner may be replaced by a gas burner or the chamber may be provided with a grate for coal, coke or other materials. Combustion air is supplied around the burner through a conduit l2 joining the opening in the bottom of the combustion chamber and leading from a blower I I 2 encased in a housing 13.

The combustion chamber 1 is provided at the top thereof with a plurality of openings l4 into which is inserted one end or leg of a number of U-shaped tubes generally indicated IS. The number of the tubes is relatively large, as indicated in Figs. 1 and 2, and the tubes are of substantial length so that they extend throughout the greater'part of the height of casing I. An annular manifold 16 surrounds and is spaced from combustion chamber 1, being suitably supported by lugs I! attached to bottom 9 of the combustion chamber or by other rigid supporting means which will readily suggest themselves.

Manifold I6 is preferably formed of a single. casting and is provided with a number of openings in the top thereof, correspondingto the number of openings in the top of the combustion chamber, for the purpose of receiving the other leg of the, U-shaped tubes I5. The tubes are provided with a machined taper at the bottom of each of their legs, whereby they may be readily fitted in and removed from the chamber and manifold for the purpose of brushing or cleaning the same internally and externally. The construction of the upper or bight ends of the tubes is clearly illustrated in Fig. 3, consisting of a U-shaped double elbow l8 joined to the individual straight uprights l9 by a machine fit joint 20. Thus, not only may the U-shaped tubes, generally indicated 15, be removed as a whole from their connection with chamber 1 and manifold "5, but also the tubes may be separated into their simplest elements for the purpose of cleaning.

For'the purpose of facilitating thecleaning of manifold I6 interiorly thereof, I have provided a plurality of clean-out passages 2| preferably integral with the manifold casting and extending tangentially of the same outwardly to openings 22 provided in the jacket. Removable doors 23 normally close the openings. It will be appreciated that this construction betters the construction wherein the clean-out passages extend radially of the furnacev casing, inasmuch as a straight cleaning implement may be inserted conveniently,

eliminating the difficulties caused by the presence of bends between the passages and manifold.

The products of combustion are exhausted from manifold l6 through a suitable flue l2l.'

Air is supplied to the casting at the left side thereof, as viewed in Fig. 1, by means of .a suitable blower 24 whose inlet is shown at 25. The outlet of the blower communicates with casting l at a point adjacent manifold ii at the bottoms of tubes l5. Accordingly, the air supplied to casficiency of combustion particularly when liquid fuel is employed.

Tubes I5 furnish a support adjacent their upper end for a humidii'yingtrough 29 which is adjustably mounted on the tubes by means of clamps Ill. The supply of liquid to the humidifying trough is made possible by means of a bent metal pipe ll carried by the casing and the supply is governed by means of a humidostat 32, preferably of the wood block expanding type, which is mounted in another room in a manner that willbe understood. Flexible tube 33 connects the humidostat with valve 34 controlled thereby.

In the above described-construction, the difflculty normally attendant on cleaning a' furnace is reduced to a minimum, due to the improved shape of the manifold, as well as the ready removability of fire tubes l5.

Efficiency of combustion is greatly improved by the nature of the tubes themselves as well as by their mounting with respect to the manifold. I have found that a large number of .connecting tubes I! of relatively small diameter and extending substantially lengthwise of the casing, as embodied in my invention, results in optimum heating. This result is enhanced by the arrangement for preheating combustion air, which is an important feature of my invention. The employment of a blower in this combination permits the useof tubes or flues for the products of combustion of relatively small diameter and the uniform discharge of the products of combustion therethrough. The air entering the casing circulates freely across the tubes which provide a large radiating surface. As the heat of the products of combustion is not relied upon to insure circulation thereof, the maximum of heat units may be utilized without affecting the discharge of the products of combustion.

I have illustrated and described may improvements in an embodiment which I have found very practical. I have not attemptedto illustrate or describe other embodiments or adaptations as it is believed this disclosure will enable those skilled in the art to embody or adapt my improvements as may be desired.

Having thus'described my invention, what I claim as new and desire to secure by Letters Patent is: I

1. In a furnace, a combustion chamber having a burner therein, said chamber having a plurality of closely spaced openings at the top thereof, an annular, manifold surrounding and spaced from said combustion chamber and having a plurality of openings at the top thereof, a plurality of closely spaced U-shaped tubes of relatively small diameter and having the legs thereof extending downwardly, oneleg in an opening in the combustion chamber and the other in an openingin the manifold, said tubesbeing adapted to receive the combustion gases from the chamber and circulate themupwardly a substantial portion of the furnace height and downwardly into the manifold, a closed casing surrounding said chamber, manifold and tubes, means for supplying air to said casing above said manifold and adjacent the bottom of said tubes, and means for circulating preheated combustion air from the casing to the burner, said circulating means including means positioned to receive and withdraw air after it passes and is heated by said tubes.

2. In a furnace, the combination with a casing,

of a combustion chamber disposed centrally at the bottom of the casing, an annular flue manifold .surrounding said combustion chamber, a

casing at an elevated position relative to the discharge of the cold air supply blower and in a position to receive and withdraw the air after it passes said tubes.

' 3. In a furnace, the combination with a casing, -,of a combustion chamber disposed centrally at burner and having an outlet communicating with said burner and an intake connected to said casing oppositesald cold air supply blower and at an elevated position relative to the discharge of the cold air supply blower.

4. In a furnace; a casing having therein a combustion chamber and a manifold for receiving the combustion gases, means connecting said chamber and manifold, comprising a plurality of closely spaced tubes of relatively small diameter inserted in said chamber and manifold, respectively, means for supp ying air to be heated to said casing comprising an air supply member communicating with one side of said casing adjacent the point of junction of the tubes with the manifold, and means for supplying combustion air to said chamber and comprising an air receiving flue communicating with saidcasing on the side thereof opposite said supply means.

' JOHN H. NOBLE. 

